remove finalizer

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1894490 13f79535-47bb-0310-9956-ffa450edef68

poi-examples/src/main/java/org/apache/poi/examples/xssf/streaming/DeferredGeneration.java

@@ -56,6 +56,7 @@ public class DeferredGeneration {
                 //writeAvoidingTempFiles was added as an experimental change in POI 5.1.0
                 //wb.writeAvoidingTempFiles(fileOut);
             } finally {
+                //the dispose call is necessary to ensure temp files are removed
                 wb.dispose();
             }
             System.out.println("wrote DeferredGeneration.xlsx");

poi-examples/src/main/java/org/apache/poi/examples/xssf/streaming/Outlining.java

@@ -47,6 +47,7 @@ public class Outlining {
             try (FileOutputStream fileOut = new FileOutputStream("outlining_collapsed.xlsx")) {
                 wb2.write(fileOut);
             } finally {
+                //the dispose call is necessary to ensure temp files are removed
                 wb2.dispose();
             }
         }

poi-examples/src/main/java/org/apache/poi/examples/xssf/streaming/SavePasswordProtectedXlsx.java

@@ -80,6 +80,7 @@ public final class SavePasswordProtectedXlsx {
             }
         } finally {
             wb.close();
+            //the dispose call is necessary to ensure temp files are removed
             wb.dispose();
         }
         TempFileUtils.checkTempFiles();

poi-ooxml/src/main/java/org/apache/poi/xssf/streaming/SheetDataWriter.java

@@ -152,6 +152,9 @@ public class SheetDataWriter implements Closeable {
      */
     public InputStream getWorksheetXMLInputStream() throws IOException {
         File fd = getTempFile();
+        if (fd == null) {
+            throw new IOException("getWorksheetXMLInputStream only works when a temp file is used");
+        }
         FileInputStream fis = new FileInputStream(fd);
         try {
             return decorateInputStream(fis);